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Bad Bolts

Are NYC skyscrapers about to fall apart?

I once read of a construction industry scandal in New York involving a supplier of large nuts and bolts used to hold together steel beams in skyscrapers. He cheated by substituting cheaper, under-spec nuts and bolts for the proper ones. Evidently several skyscrapers were built using these inferior connectors. The cost to retrofit the buildings would be in the billions of dollars, and only a few have been repaired. What is the chance one or more of these buildings will collapse primarily because of the fraud? Which streets in Manhattan should I avoid, lest one of these behemoths topple as I pass by? —R. Wolin, Boston

That sounds pretty scrambled, bud—I think you’ve got a couple separate stories mixed up. One involves Citicorp Center in midtown Manhattan, which was placed in peril of collapse when bolted joints were substituted for stronger welded ones to save a couple bucks during construction. The other is the equally frightening phenomenon of counterfeit nuts and bolts, which when surreptitiously used instead of the genuine article can (and do) result in catastrophic failure and death.

Citicorp Center first. This 59-story building, completed in 1977 and now known as 601 Lexington Avenue, has two notable features: first, a distinctive slant-topped profile, and second, four main supporting piers, nine stories tall, each located in the center of one of the sides of the building’s square footprint rather than in the corners.

The latter evidently flummoxed some participants in the construction process. Although the building as originally designed could withstand the expected wind loads, the contractor came up with the aforementioned idea of substituting bolts for welds in the building’s wind-bracing system. This wasn’t inherently crazy, but (among other regrettable decisions) engineers evaluating the change’s impact failed to calculate the effect of winds striking the building at a 45-degree angle rather than straight on.

Not long after completion, the lead structural engineer realized the building could be toppled by a storm of a severity that on average was seen in New York once every 16 years. The owners spent a frantic summer strengthening 200 bolted joints with welded-on steel plates, working on weekends when the building was unoccupied. The danger thus averted didn’t become public knowledge till a 1995 article in the New Yorker.

To be clear: while bolted joints are cheaper and inherently weaker, nothing I’ve seen suggests their use in Citicorp Center was sneaky or that the bolts themselves were substandard. We found no cases of shady dealing by a vendor endangering major buildings in New York or elsewhere. The fact remains that in this age of global supply chains, shoddy counterfeit fasteners pose a real danger.

Bolts, nuts and other fasteners are commonly rated for strength, corrosion resistance and so on. For example, a Society of Automotive Engineers grade 1 bolt can hold 60,000 pounds per square inch (PSI) before breaking, while a more expensive grade 8 bolt can hold 150,000 PSI. High-performance fasteners are typically stamped with special markings, but it’s not hard to create fakes from inferior materials at lower cost. These have been blamed for numerous deaths:

• In 1989 counterfeit bolts holding together the tail of Partnair Flight 394 came loose, causing the aircraft to disintegrate at 22,000 feet, killing all 55 aboard.

• Counterfeit bolts were blamed for a 1985 accident involving a U.S. Army self-propelled howitzer, in which the mechanism that elevates the gun snapped its bolts and crushed a soldier.

• Counterfeit bolts were suspected in two fatal crane accidents in the 1980s—more about this directly.

Bad bolts have also been cited as the cause of two military helicopter accidents, toxic industrial leaks and a broadcasting tower collapse, all resulting in fatalities. The Astro I space lab, launched in 1990, had to be reassembled at a cost of more than $1 million when it was discovered defective bolts had been supplied by a shady outfit operating out of a condominium garage.

Most of these cases happened prior to 1990. In that year, following reports that nearly 400 people had been killed over a 15-year period in accidents caused by counterfeit nuts and bolts, Congress passed the Fastener Quality Act, which levies stiff fines against suppliers of substandard product. Perhaps as a result, bolt horror stories have subsided although not disappeared. In 2012 a company called Kustom Products was indicted for selling fake main rotor locknuts for Kiowa helicopters to the U.S. military. (The fastener in question is popularly known as the “Jesus nut,” presumably because if it fails you’ll be seeing Jesus soon.)

Back to those crane accidents. One of them happened when a construction crane fell off a building in New York, giving us the following confusing situation: a. a Manhattan building was endangered due to a weakness involving bolts, but not due to fake bolts; b. Many people have nonetheless been killed due to bad bolts; c. A few of said fatalities were in New York, but d. none lately as far as I know—recent NYC crane collapses have involved things like faulty ropes or Hurricane Sandy. Slim comfort, but at least you’ve got the facts.